It is known that, in such a phase of horizontal flight at low speed, the lift imparted on the aircraft by its wings and said flaps, then in the extended position, needs to be high, such that this high lift, reinforced by the blowing on the wings and the extended flaps by the airscrews of the engines and aided by the thrust of said engines, generates a high pitch-down moment relative to the center of gravity of the aircraft.
To balance the aircraft, the pilot deflects said adjustable horizontal tail group to nose up, so that it generates, relative to the center of gravity of the aircraft, a nose-up moment to counteract said high nose-down moment. This balancing nose-up moment must therefore be high, such that the local impact on said adjustable horizontal tail group is strongly negative.
The result is that if, during such a phase of flying horizontally at low speed, the pilot orders a dive, for example to abruptly avoid another aircraft by flying under it to avoid a collision or to rapidly regain speed, the local impact on said adjustable horizontal tail group risks exceeding the stalling effect of the latter, such that, at the moment when the pilot wants to stop the dive maneuver, the adjustable horizontal tail group may have lost its effectiveness: the aircraft will therefore be incapable of priming a flare and this could result in the loss of the aircraft.